Pond Boss Forums STOCKING A NEW POND Types of fish to choose trout in pond.

That might work, using the ground as a heat sink. You might want to play with the water flow thru the coils. Just like a car radiator won't cool the motor if a thermostat or a reducer is in the system to reduce the flow. The dwell time in the "radiator" has to be sufficient for the water to lose some of it's heat.

Thinking a bit, it might be even better if the coils weren't anyplace where they would influence the water, i.e. buried outside of the pond basin.